Self-Defense?

I think Fred Kaplan's "War Stories" are some of the most insightful and interesting articles on Slate.com, and yesterday's was no exception. But, to my mind, there was something problematic here:

"Nearly every nation has an interest in halting, detouring, or at least slowing down the Iranian mullahs' quest for atomic bombs. But, as even most critical observers acknowledge, one motive for the Iranians is self-defense—to deter an attack, principally by the United States or Israel."

Ok, fair enough. But does that mean they'd stop their program if they had infinite assurance that nobody would attack Tehran to "bring democracy" to their country? True, if Iran has nuclear weapons, Israel sure as hell better think twice about attacking them. And so should the United States, but not because they'll nuke us if we do. It's because if we attacked them they'd nuke Israel. In fact, no nation that could conceivably attack Iran has to worry about any possible direct retaliation at all, except Israel (and maybe a sliver of Russia). If every free nation on the planet EXCEPT Israel agreed that Iran needed to be militarily engaged, their deterrent would be threatening to bomb Tel Aviv. In that sense, their program is about self-defense.

Here's a question, though: If the Iranian government can--as I write--get away with operating a nuclear-weapons program based on the possibility that they'll annihilate Israel if challenged, could they also get away with helping Iraqi Shiites ethnically cleanse Sunni's in Baghdad based on the same threat? Torturing dissidents? Sabotaging Lebanese Democracy? How much leeway do they get ? That's not exactly self-defense anymore, but a fairly perverse brinkmanship that gives them the power to corrupt the region in a way that's asymmetric to their actual resources.

What this means is that it's important to figure out what the limits of their power are? And if those limits are unacceptable, it might mean that Iran will ultimately force the question: Can Israel maintain hostilities with neighbors that are becoming armed with nuclear weapons, or is Israel as we know it doomed one way or another no matter what they do?